From nobody Sun Feb 8 23:25:45 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD2D0C53210 for ; Fri, 6 Jan 2023 01:17:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233839AbjAFBRa (ORCPT ); Thu, 5 Jan 2023 20:17:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232814AbjAFBQa (ORCPT ); Thu, 5 Jan 2023 20:16:30 -0500 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF8C765AF2 for ; Thu, 5 Jan 2023 17:14:22 -0800 (PST) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-47ede4426e1so3120787b3.7 for ; Thu, 05 Jan 2023 17:14:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=0PXIy8RA30k82n5MqadBULMYpw3jcQQNxAI0MLkfm2o=; b=ARYzhqPubKAcUMlq5dSBX0xvRbkdMD3Z7If0ag7prbjxIne2GkJ8lAhHrtaEOpMtq7 wIIAhYz1/Ajx9d5Cslo0C4NAiwSy8WApA2ndyhaXFs6IngyBWHUw8/RvgrKmAvHUhpkO cyOgu6KCI3mBFPHHb5Py5lPdjDvIYKL4PgTbXDJoeb9G5AmvTkBPp7JhJ96D5XJeOmNF H71WGUwe4Z9AK+ykt/tiEyDRK2He33wLTdGnjX2xFBC78IVPGeo7k2WIXLG0DcCUuoTc xxOGpURmrBMBR/Kj4dorDzcHumIWTMXaSANO4lHr0MkNbDkcual08RTxiy0tgP3OCVKT 4hUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=0PXIy8RA30k82n5MqadBULMYpw3jcQQNxAI0MLkfm2o=; b=vCoZhtwVQpHeNmymXkVIXtq6YTrS0tyIqlCkjrrekGFFl53Rtoo3B1N/KlycD2Fb0R inpI0m8i+kQw3MpObC4qQyIMz2Z1tIy5TpDvlq3RBl+ADVXQmmDIiVydzl5NpJSIcYC1 KeAmaW4VC+/MBpGuaoiM95H5IKgLGj1zOP++vrXLeqgbJhFR6fPUlX+Ku/6+lBFYxgXJ lm1U0x90ROO8J+IgZqj0aVpHo+R5ap1QOr2Fq2ed15qFZn3/3KusB1PYZzfi5PfxHEzZ OXmZ/wkJ3LIbGCIAf0kUFXzDbFERG2DswQ3sXIj4uNgRUFyi+AnO+DCh80zn/CXdCOIR SP2w== X-Gm-Message-State: AFqh2kr8f4nPYGfjD/IgnOS9KPZ1FxuK/9XcxtQj0dhPoWcoF2mw21WL W3J3z0QJhvMYIQEO6Q0U3DrYEUr0Zo8= X-Google-Smtp-Source: AMrXdXt4VBg4zaH9HqqIlH27H/G6sq0m1dLXG6txeQ75uTMkvGpBIpTSTbajtVV7xXJrKV//LkmnjgWpK6g= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:d095:0:b0:7b6:daae:ad50 with SMTP id h143-20020a25d095000000b007b6daaead50mr235713ybg.89.1672967643231; Thu, 05 Jan 2023 17:14:03 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 6 Jan 2023 01:13:02 +0000 In-Reply-To: <20230106011306.85230-1-seanjc@google.com> Mime-Version: 1.0 References: <20230106011306.85230-1-seanjc@google.com> X-Mailer: git-send-email 2.39.0.314.g84b9a713c41-goog Message-ID: <20230106011306.85230-30-seanjc@google.com> Subject: [PATCH v5 29/33] KVM: SVM: Ignore writes to Remote Read Data on AVIC write traps From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Alejandro Jimenez , Maxim Levitsky , Suravee Suthikulpanit , Li RongQing , Greg Edwards Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Drop writes to APIC_RRR, a.k.a. Remote Read Data Register, on AVIC unaccelerated write traps. The register is read-only and isn't emulated by KVM. Sending the register through kvm_apic_write_nodecode() will result in screaming when x2APIC is enabled due to the unexpected failure to retrieve the MSR (KVM expects that only "legal" accesses will trap). Fixes: 4d1d7942e36a ("KVM: SVM: Introduce logic to (de)activate x2AVIC mode= ") Signed-off-by: Sean Christopherson Reviewed-by: Maxim Levitsky --- arch/x86/kvm/svm/avic.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 2c6737f72bd4..ff08732469cb 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -628,6 +628,9 @@ static int avic_unaccel_trap_write(struct kvm_vcpu *vcp= u) case APIC_DFR: avic_handle_dfr_update(vcpu); break; + case APIC_RRR: + /* Ignore writes to Read Remote Data, it's read-only. */ + return 1; default: break; } --=20 2.39.0.314.g84b9a713c41-goog